It is often important to seal rotating shafts emerging from a bearing and its housing to prevent lubricants associated with the bearings from leaking externally of the housing or bearing and for preventing contaminants in the environment from proceeding through the seal and into the lubricant of the bearings.
Labyrinth seals as described in U.S. Pat. No. 4,706,968, and the prior art cited therein, depend upon forming labyrinths between a plurality of rings where at least one of the rings is stationary and one of the rings rotates with the shaft. These sealing structures are also designed to prevent contaminants from entering the lubricants in the housing.
U.S. Pat. No. 4,706,968 provides a third ring member to improve sealing of the labyrinth interfaces. The third ring also allowed for axial separation of the fixed or stationary ring and the rotating ring while maintaining a seal. This axial separation is the result of axial shaft displacement normally in an outward direction away from the bearing and housing. However, the third ring has not proved as successful as expected in controlling contaminant entrance during the axial shaft movement or axial shaft displacement.
Although the third floating ring solved a great number of problems, problems relating to axial shaft displacement are still encountered in various applications. This invention is designed to eliminate the problems resulting from axial shaft movement or displacement.